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Periodicity in recA protein-DNA complexes
A A Volodin1, H A Smirnova, T N Bocharova
1Institute of Molecular Genetics of the Russian Academy of Sciences, Moscow.
FEBS Letters
|May 5, 1997
Summary
RecA protein forms ordered complexes with DNA, influencing guanine accessibility. This structural order is consistent across DNA strand exchange and renaturation, revealing insights into RecA-DNA interactions.
Area of Science:
- Molecular Biology
- Biochemistry
- Structural Biology
Background:
- RecA protein is crucial for DNA repair and recombination.
- Understanding RecA-DNA complex structure is key to elucidating its functions.
- Previous studies have explored RecA's role in DNA strand exchange and renaturation.
Purpose of the Study:
- To investigate the structural arrangement of RecA protein on double-stranded DNA.
- To compare DNA states in RecA complexes formed during strand exchange and renaturation.
- To determine the influence of RecA binding on guanine residue accessibility.
Main Methods:
- Studied the reaction of guanine residues with dimethylsulfate.
- Utilized complexes of RecA protein with fluorescent dye-tagged double-stranded oligonucleotides.
- Analyzed patterns of dimethylsulfate modification to infer DNA accessibility.
Main Results:
- Dimethylsulfate modification patterns indicate similar DNA states in RecA complexes formed by strand exchange and renaturation.
- Guanine modification efficiency showed a periodic variation with a 3-nucleotide period along the oligonucleotide axis.
- This periodicity suggests a highly ordered arrangement of RecA monomers on the DNA.
Conclusions:
- The RecA protein forms a strictly ordered structure along the DNA.
- The reactivity of guanine residues is dependent on their specific binding site within a RecA monomer.
- The structural organization of RecA-DNA complexes is conserved across different functional states.